Afriend of yours, a senior, took the graduate record exam in september and scored in the 99th percentile. in february your friend took the same exam over again. this time your friend scored in the 84th percentile. as a research methodology student, you told your friend that his/her lowered score was probably due to:

Step-by-step explanation:

To calculate the 99th percentile you must  order scores from least to greatest, and the one that occupies the position that corresponds to 99% of n-scores is the 99th percentile.

The 99th percentile of a set of observations ( in this case, exam scores) is a value such that 99% of the observations are less than or equal to him and the remaining 1% is greater than or equal to him.

If he is now in the 84% is because there are some people that took the exam in February that are better than him, they had better scores and then, 84% of the observations are less than or equal to him and the remaining 16% is greater than or equal to him.

Before there were only 1% scores that were better than his or her score. Now, there are 16% scores that are better, then people got better scores in the February exam, compared to your friend's score.